Best Open-Source AI Agent Frameworks in Python 2026: 10 Compared with Stars

Choosing a Python agent framework in 2026? These 10 open-source options with real star counts make it easier.

💡 What You Will Learn

Choosing a Python agent framework in 2026? These 10 open-source options with real star counts make it easier.

📜 Table of Contents

• Best Open-Source AI Agent Frameworks in Python 2026
• The rankings
• How to choose
• Minimum viable agent in CrewAI
• FAQ

Best Open-Source AI Agent Frameworks in Python 2026

All star counts below come from the ainomam GitHub star tracker snapshot dated 2026-07-31.

The rankings

1. LangGraph - 38,573 stars (part of LangChain 143,097). Stateful, graph-based agent orchestration. The 2026 default for production.
2. AutoGen - 60,129 stars. Microsoft multi-agent conversation framework; now with AutoGen Studio for visual building.
3. CrewAI - 56,432 stars. Role-based crews; the friendliest onboarding in the ecosystem.
4. LlamaIndex - 51,260 stars. Agents deeply integrated with RAG pipelines and 40+ data connectors.
5. Phidata - 41,526 stars. Agent platform with built-in UI, monitoring, and tool integrations.
6. Haystack - 26,073 stars. Production-oriented agent orchestration with strong evaluation tooling.
7. Semantic Kernel - 28,396 stars. Microsoft cross-language framework (C#/Python).
8. TaskWeaver - 6,176 stars. Code-first agent framework; good for data workflows.
9. Eliza - 18,856 stars. Agent framework with a focus on social and autonomous agents.
10. AgentVerse - 5,091 stars. Research-focused multi-agent simulation framework.

How to choose

• Production SaaS: LangGraph
• Quick prototype: CrewAI
• RAG-heavy apps: LlamaIndex
• Multi-agent research: AutoGen or AgentVerse
• Enterprise, polyglot teams: Semantic Kernel

Minimum viable agent in CrewAI

[python] from crewai import Agent, Task, Crew researcher = Agent(role="Researcher", goal="Find facts", backstory="A careful analyst") task = Task(description="Summarize MCP adoption in 2026", agent=researcher) crew = Crew(agents=[researcher], tasks=[task]) print(crew.kickoff()) [/python]

FAQ

Which framework has the most stars? AutoGen (60,129), followed by CrewAI (56,432). Can I combine frameworks? Yes, many teams use LlamaIndex for retrieval inside a LangGraph orchestration layer.

❓ FAQ

Which framework has the most stars?

AutoGen (60,129), followed by CrewAI (56,432).

Can I combine frameworks?

Yes, many teams use LlamaIndex for retrieval inside a LangGraph orchestration layer.